| Model Name | #Dimension | #Layering | Language | #Subroutines | #Lines | Time Step | Hardware |
|---|---|---|---|---|---|---|---|
| Australian | - | - | Statistical regression model run on Excel spreadsheet | - | - | Daily | Any |
| BAIM | 1D | 3 | FORTRAN | 29 | 5000 | 1 hour or less | - |
| BASE | 1D | 1 | FORTRAN | 4 | 357 including comments | Host model determined - 20-30 mins usually | anything - runs on SGi, PCs, Suns, CRAY etc. |
| BATS | 1D | 1 mass and 2 thermal layers | FORTRAN 77 | 7 | 1019 | 5 minutes to 3 hours, mostly 20-30 minutes | PC or UNIX computers |
| CLASS | 1D | 1 | FORTRAN | Many | Numerous | 30 minutes (specified by user) | PC or UNIX computers |
| CROCUS | 1D | 50 (variable depth) | FORTRAN 77 | 23 | 1800 effective lines | 900 seconds | most unix workstations |
| DARSSM | 1D | 4 | FORTRAN | 7 (incl. soil model) | 3000 | 20 to 30 min | - |
| DHSVM | 1D | 2 | C | 5 | 1550 | 24 min to 1 hour | Unix workstations (SUN, HP) and Pentium class PC's |
| ECHAM (Duemenil) | 1D | 1 | FORTRAN | 1 | - | not fixed (GCM: 24; input data: 1 h to 3h) | Cray |
| ECHAM (Loth) | 1D | 2-5 | FORTRAN | 7 | - | not fixed (GCM: 24; input data: 1 h to 3h) | Cray |
| GFDL Snow Model | 1D | 1 | FORTRAN 77 | - | - | Same as GCM | - |
| Hadley Centre/UKMO GCM LSM | 1D | 4 soil layers. Snowpack is included in surface soil layer. | FORTRAN | 20 | 5000 | 30 minutes in climate GCM | - |
| HBV | 1D | 1 | Most in FORTRAN, newest in C++ | 4 major parts | Depending of programming strategy (a few to thousands) | one day | DOS on a ordinary PC (for instance, a 386), newer versions demand Windows-95, NT or unix |
| IAP94 | 1D | 3 | FORTRAN 77 | 10 | - | 30 min to 1 hour | Convex C3-120, SGI workstation, DEC workstation |
| IHACRES Snow Model | 2-3D | 1 | FORTRAN 77 | 10 | 2000 | Daily | SUN. Probably Pentium is OK, but with large hard disk |
| INM | 1D | The model treats the snowpack as a unique layer, but the freezing depth subdivides the snowpack into a dry surface layer and a humid layer | FORTRAN 90 | 9 subroutines. The main one treats the internal evolution | 300 effective line | flexible according to input data (e.g. 1 hour) | - |
| ISBA | 1D | - | FORTRAN 90 | 4 subroutines | The snow code is embedded in the ISBA land-surface scheme, whose "off-line" version includes about 1350 lines | between 5 and 30 minutes | PC or work station |
| ISBA-ES | 1D | 3 | F77 and 90 | approx 25 subroutines | F90 2326 total lines: of which less than approximately 50% are actual executable lines of code: the rest are comments. | between 5 and 30 minutes (time scheme is fully implicit) | The code has been compiled and run on: F77: UNIX HP workstation, Linux PC 199 GHz Pentium F90: UNIX HP workstation, CRAY ymp, Fujitzu (similar to CRAY) (Code in F77 is scalar, F90 has 2D or 3D options) |
| LSMCS | 1D | 3L | FORTRAN | 28 subroutines and functions | more than 2000 lines | 1800 seconds | any type of hardware |
| MAPS/RUC SVS | 1D | 1L | F77 with extensions | Three subroutine | Approximately 500 | 5-min time step is used in MAPS/RUC forecast model | No special requirements. |
| MAR | 1D | ML | F77 | 17 | 4898 (2382 effective lines) | 6 minutes | Any unix workstation (model has been used so far on DEC and HP workstations) |
| Mosaic | 1D | 1L | FORTRAN | There are specific lines regarding snow in several of the LSM subroutines | - | Between 5 and 20 minutes | many different systems |
| MRI-CGCM GHM | 1D | 1L | Fortran 77 | 5 | 1052 | 1 hour | super computer; Hitachi s-3800 |
| MU-SNW | One dimensional, but includes information about the sub grid scale topography. | 1L | FORTRAN | About 5 | About 300 | About 20 min | very portable |
| NCEP/OH/OSU CAPS | 1D | 1L | FORTRAN 90 | one primary subroutine and significant parts of 3-4 other subroutines | about 250 | 10-60 minutes | UNIX workstation or UNIX mainframe (e.g. CRAY) |
| NCEP/OH/OSU CAPS | 1D | 1L (snow), 4L (frozen soil) | FORTRAN | 9 | about 700 | Snow-frozen ground model time step depends on a land surface required time step that is usually 30 minutes | UNIX workstation |
| NWSRFS SNOW-17 | - | - | Fortran | - | - | - | - |
| RAMS Snow Component | 1-D | 1L | Fortran | Most code contained within two subroutines, but interspersed with code for soil temperature determination and soil hydrology | Approximately 30 dedicated to snow | 90 seconds, dictated by atmospheric component of the model | RISC-based workstation. I use an HP 735 and will soon acquire an HP C180 |
| RGM | Horizontally distributed, vertically lumped | One snowpack layer | Interactive Data Language (IDL) | Approx. 20 procedures plus a programming library of hundreds of procedures and functions for a large variety of purposes (e.g. GIS, RDBMS, mapping, math ...) | More than 1000 lines without the library code (rapidly increasing) | User-selectable (typically 1 hour) | Each system supporting IDL (PC, VMS, Unix, Mac, SG) |
| SEMS | One-dimensional energy balances, 3-dimensional snow distributions, that evolve in time. | Multi-layers, layers defined depending on application; usually identified by a continuous precipitation event. | FORTRAN | about 55 | about 4000 | Determined by individual application; typically 30 minutes to a day | run on UNIX workstations. |
| SHAW | One-dimensional profile model | The model will break the snow pack into layers; the thickness of the layers will depend on its depth within the snow pack. The surface layers will be approximately 2 cm thick and the layer thickness will increase with depth.Layers at a depth of 2 m will be about 10 cm thick. | FORTRAN | 77 total subroutines; approximately 10 dealing specifically with snow | 9000 total linesof code; approximately 950 directly related to snow | Hourly or daily | None recommended; the model is very transportable between hardware |
| SLURP | one dimensional applied to areas of common land cover | one layer | FORTRAN 90 | integrated in larger model | 50? | daily | Pentium |
| SNAP | One-dimensional | Currenly "effective pack"= one layer, but a multiple layer version is currently under development. | FORTRAN | 12 | approx 2500 | Since it uses a new analytical formulation for water movement through the pack (eliminating the need for matrix computations), there is no restriction on the time step. The time step is dictated by the frequency of the input data. Hourly input data is currently what we are using | 486 pc or better |
| SNOWPACK | 1D (operational), 2D (research) | Finite Element layers, with each snowfall new layers/elements are added | C | Many | approx. 20000 including comments | Typically 15 minutes | UNIX/PC |
| SNTHERM | 1D | Unlimited and arbitrary - changes during run. | FORTRAN 77 | 66 | 10993 | Model uses adaptive time step which adjusts to meet convergence criteria (much smaller step during water flow). User inputs max and min of range. Max is equal to or less than time step of input meteorological data | PC or UNIX |
| SNTHERM (Davis) | 1D | Unlimited and arbitrary - changes during run | FORTRAN - SNTHERM; spatial distribution => UNIX shell and C | 75 | 10993 | Model uses adaptive time step which adjusts to meet convergence criteria (much smaller step during water flow). User inputs max and min of range. Max is equal to or less than time step of input meteorological data | SNTHERM - PC, MAC or UNIX spatial distribution - UNIX |
| SNTHERM.ver4 | One-dimensional, with three D radiative transfer | ca. 20 | SNTHERM: FORTRAN , calls shellscript which calculates parameters for DISORT radiative transfer program (Stamnes et al. 1988); UNIX | Extra; 2 + DISORT (many) | - | variable. Hourly data | UNIX |
| SOIL | 1D | 1L | FORTRAN | The whole SOIL-model has about 77 subroutines, one of which is the snow-subroutine. | ca. 100 | It is set by the user, often hourly or daily inputs. | PC |
| SSMI DSCM | TWO. WE IDENTIFY SNOW AT 1/3 DEGREE PIXEL RESOLUTION | - | Fortran | 4 | 25 LINES | DAILY | A DESCENT PC | SPONSOR | 1D | 2 (at both boundaries of snow cover) | FORTRAN | 4 subroutines for the snow block only and 3 subroutines dealing with the snow characteristics. | About 400-450 (some operators deal not only with snow) | 30 to 60 minutes | No specific recommendations. |
| SPS (CAPS-LLNL) | single snow layer on top of multiple soil layer | 1L | Fortran | - | - | 5 min - hours (usually 5 min for coupled model, column version was run up to 3-hr steps). | workstations - CRAY |
| SSiB | 1D | 1L | FORTRAN | 3 | about 100 lines | from 2 min to 1 hour | no |
| TSCM1 | 1D | 1L | FORTRAN and BASIC | One | 150 | One hour | PC |
| TSCMM | 1D | the thickness is 2cm number of layers depends on snow depth | FORTRAN | 14 | 600 | 200 sec | PC or work-station |
| UEB | 1D | 1L | FORTRAN | About 10 | About 600 | Flexible but longer than 6 hours not recommended | Any with a Fortran compiler - Has been successfully run on Sun Solaris, IBM RS6000 and Intel 486 and Pentium hardware. |
(Prepared by Zong-Liang Yang and Guo-Yue Niu)